An RFID (Radio Frequency Identification) system is a contactless recognition system for transmitting and processing object information and work environmental information.
An RFID system that has appeared since 1980s is called a radio recognition system, a radio frequency identification system or a radio identification system.
RFID systems are basically comprised of an RFID tag storing data, and an RFID reader having a reading function of data stored in the RFID tag.
The RFID tag is comprised of an RFID tag chip and an antenna manufactured in semiconductor, and may be categorized into a passive type and an active type based on operation characteristic.
A passive type is a formation of operating by supplying energy from a propagation signal of an RFID reader, and an active type is a formation of an RFID tag embedded with an electric cell for unaided operation.
Radio frequency identification technologies used in an RFID system have advantages of a direct contact like a barcode or an unnecessary scanning within a visible light band.
Owing to such advantages, an RFID system has been evaluated as a barcode system-replaceable system and has a prospect of its availability range also expanding steadily.
As an RF (Radio Frequency) band used in an RFID system, there exist 30-500 kHz band as a low frequency band, 850-950 MHz and 2.4-2.5 GHz bands as high frequency bands.
Herein, a low frequency band has a relatively short recognition range, that is, lower than 1.8 m, and a high frequency band has a relatively long RF recognition, that is, more than 27 m.
Hence, depending on whether a recognition range should be long or satisfied to be only short, it is possible to apply and employ an RFID system using an RF signal of a corresponding frequency band.
Such an RFID system is attached on a certain item, and comprised of an RFID tag storing information on that item, and an RFID reader communicating with the RFID tag.
The RFID reader modulates and sends out an RF (Radio Frequency) signal having a specific carrier frequency.
When an item attached with the RFID tag is placed within a read zone of the RFID reader, the RFID tag receives a signal sent by the RFID reader, and transmits pieces of predefined information stored in an intra-memory to the RFID reader in response to a received signal.